Abstract：The eigenmatrix of the light propagation in photonic crystal are deduced by the plane-wave expansion method. The dispersion curves of two dimensional square lattice and triangle lattice photonic crystals composed of circular air cylinders are calculated by numerical calculation, respectively for vertical incidence. And the dispersion curves of triangle lattice photonic crystals also are calculated for oblique incidence. Based on the calculation and analysis, it is indicated that the band gaps of E wave and H wave of two dimensional triangle lattice in <10> direction and <11> direction for vertical incidence all appear, and they are wider than that of square lattice; the dispersion curves of two-dimensional triangular photonic crystal in the oblique incidence are moved upward with the angle of incidence increasing, and band gap center frequency also increased, however the band gap width has been reduced accordingly until it disappeared. These studied results are significant for making photonic crystal elements and putting them into applications.
2011, Vol. 29 
